Andrew Davidson

Senior Staff Engineer, MKS Newport - New Focus

Andrew Davidson is a Senior Staff Engineer at MKS Newport - New Focus (Irvine, CA).

FIGURE 1. Devices for detecting the position of a laser beam include: a) a position-sensitive detector (PSD), b) a quadrant-cell detector (quad cell), and c) a CMOS camera. The X and Y beam position on both the PSD and quad cell can be calculated from the detectors’ current outputs iA, iB, iC, and iD. The beam position on the camera is determined by finding the beam’s centroid.

DETECTORS: CMOS cameras allow robust active stabilization of laser beams

Aug. 1, 2011
Accurate measurement of the position of a laser beam can be achieved in several ways, each with its strengths and weaknesses. A comparison of these has resulted in an active beam...
FIGURE 1. The impulse response (blue) of a 4-GHz receiver was measured with a 1-ps, 1530-nm pulse on a 50-GHz oscil­loscope. The step response (red) was then calculated by integrating the impulse response, which can be used to derive the eye diagram.
Detectors & Imaging

Photodetector impulse response yields eye-diagram information

July 1, 2005
The eye diagram of a photo­receiver is a key ingredient in assessing performance of an optical-communications network.
Indium gallium arsenide detector, designed for use in the laboratory, has a 45-GHz bandwidth and operates at wavelengths from 950 to 1650 nm.
Detectors & Imaging

Demand for high-speed detectors drives research

April 1, 1998
Resonant-cavity enhanced detectors improve detection and wavelength selectivity; high-power traveling-wave detectors increase dynamic range of analog fiber links.